High Index Lenses

Why Are My High Index Lenses So Thick?

After you pull out your credit card and make your final purchase, you may notice that your high index lenses are thicker than you envisioned. You will need to do some research and follow the guidelines below to minimize the thickness of your high index lenses.

If you have glasses or are familiar with the eyewear industry, you may have heard lots of talk about high index lenses. High index lenses, while they may cost more than a standard pair of lenses, are known to be light and comfortable. They feel lighter on your face and remove the need to squint or constantly adjust the way that your glasses are positioned on your face. Because of this, you may go to your local or online eyewear retailer and feel compelled to purchase high index lenses.

So, what gives?

Ultimately, purchasing high index lenses doesn’t guarantee that you will have the thinnest lenses on the market. Because of this, it is worth your time to further examine why high index lenses are generally thin and what you can do to reduce some of the thickness in high index lenses.

Reducing Thickness in High Index Lenses

To start, it is helpful to understand why high index lenses tend to be thinner than your standard pair of lenses. High index lenses, along with your everyday pair of lenses, work to correct your eyesight by bending light as it passes through your lens. Along with this, the material that actually makes up your lenses has a so-called refractive index. This refractive index determines how well that your lens can actually bend the traveling light.

To put it simply, a lens is considered to be a high index when its refractive index is higher than the refractive index of plastic or other standard lenses. High index lenses typically start at around 1.60 and travel up to about 1.74. Therefore, standard lenses are those that have refractive indexes of less than 1.60. As the refractive index increases, the general rule of thumb is that the lens will get thinner.

Understanding these basic facts about high index lenses, let’s return to the question of why they may seem to be thicker than you would expect. There are several possible reasons and they aren’t mutually exclusive.

As for the first reason, let’s return to the refractive indexes of high index lenses. All high index lenses are not created equal. To reiterate, as the refractive index increases, they will generally be thinner than lenses that have a lower refractive index. 1.67 high index lenses, for instance, are thinner than 1.60 high index lenses.

You can imagine where some of the confusion emerges. Even though you may be purchasing lenses that are technically high index lenses, they may be toward the lower end of the refractive index range. Therefore, there may be a slight gap between expectations and reality, giving you the impression that you have thick lenses because you are not purchasing the thinnest high index lenses.

From there, your high index lenses may be thicker than you anticipated due to the strength of your prescription. Here, we need to return to some more basics. As an individual’s prescription gets stronger, the lenses need to compensate for that strong prescription. For example, if you are nearsighted, your lenses need to be thinner in the center but thicker at the edge of the lenses. If you need a stronger prescription to correct severe nearsightedness, however, the edges of your lenses will need to be thicker.

Therefore, a stronger prescription tends to result in thicker lenses. Even though high index lenses are naturally thinner than plastic lenses, this same principle applies to them. These lenses may still look thick due to your particular prescription. The flip side, however, is that these lenses will still be significantly thinner than plastic or other conventional lenses. Plastic lenses with a strong prescription can give off a “bug-eyed” look that many wearers find unattractive. High index lenses with a strong prescription make it much less likely that you will experience this effect.

Beyond different refractive indexes and your prescription strength, your high index lenses may appear thick due to your frames. While you may initially think that your frames don’t have much to do with the apparent thickness of your high index lenses, they can certainly play a part in making you feel like they are extremely thick.

This is because of several reasons. First, your lenses will appear thicker if you select a large frame or a rectangular frame. At Rx-Safety, you can see that we offer frames in a wide range of styles and sizes. Some of the frames that can encounter are arranged by certain categories, like rectangle, rimless, oval, square, wayfarer, and more. To check out all of our options, feel free to use all of the filtering options on the left side of a category page.

In any event, the simple fact is that the frame style may make your lenses appear thicker than other high index lenses. It is simply the way that large or rectangular frames are structured. There is nothing inherently wrong with your high index lenses. Therefore, if you are purchasing high index lenses because of their thin nature and the way that they look, you may want to avoid some of these larger frames. While it may not overcome some of the other issues that contribute to seemingly-thick lenses, it is worth considering—especially if you are not attached to a particularly large or rectangular frame.

Along with large or rectangular frames, your high index lenses may appear thicker due to the frame’s material. On our website, you can also see that our frames are made of several different types of materials. Some of those materials include acetate, metal, plastic, spring hinge, and titanium. While each of these materials has its pros and cons, some materials are better suited for high index lenses than others. To put it simply, frame choice is equal to lens choice. A large metal frame, for instance, will make high index lenses look quite thick while a small plastic round frame will make them look thin. Once again, if you are especially sensitive to the aesthetic benefits of high index lenses, you will want to make sure that you do your research before purchasing your frames. Even though it may not seem intuitive that your frame material will affect the apparent thickness of your lenses, rest assured that it will.

Explaining the Thick High Index Lenses

The reasons outlined above can explain why your high index lenses seem extra thick. The simple fact is that purchasing high index lenses will not automatically guarantee that your lenses are thin. Instead, you will need to do some research and follow the guidelines above to minimize the thickness of your high index lenses. By doing so, you will avoid any disappointment and will make the best possible purchase.

At Rx-Safety, we love answering questions about these topics. If you are searching for a frame to complement your high index lenses or simply have questions about what we discussed above, we invite you to contact us. To get in touch, you can click the contact tab above. Best of luck in finding the best high index lenses and frames for you!